You already know that to lose weight there are things you need to take out of your diet: dump truck-size plates of pasta, shoe boxes full of sugar doughnuts, fast-food soft drink cups big enough to sleep in... 

But here’s the easy part: Add more fruits, vegetables, and even tofu to your diet, and—over time—you’re practically guaranteed to end up with a healthier weight, according to a 24-year-long Harvard study involving more than 117,000 people. The researchers surmise these foods are especially beneficial because they boost satiety and have relatively few calories.

Researchers interviewed subjects every four years and found that, over each four-year period, people who ate more veggies and fruits gained less weight overall (the average gain was 1lb). Big citrus eaters gained 0.23lb less; veggie eaters, 0.25lb less; fruit eaters, 0.53lb less; berry eaters, 1.11lbs less; apple/pear eaters, 1.24lbs less; and tofu/soy eaters a whopping 2.27lbs less. (Damn you, vegetarians!)

Be careful with starchy vegetables like corn, peas, potatoes, cabbage, onions, and winter squash, though. People who ate more of these veggies—particularly corn, peas, and potatoes—gained a little bit of weight, likely because they have more natural sugar and more extra calories. Read on for the exact fat-melting foods.

DOWNLOAD The 21-Day Shred app for iOS to get the full training program, diet, and more. No iOS? No problem. Get a COPY of the PDF.